The electronic screen on the front of the Nasdaq stock market announces the listing of Facebook shares that begin trading, Friday, May 18, 2012, in New York. The biggest Internet IPO may overshadow, at least temporarily, Europe's debt crisis, which has rattled the stock market.

U.S. stock futures rebounded Friday as leaders of eight of the world's biggest economies began to gather outside of Washington to determine how best to limit damage from the debt crises rattling Europe.

Perhaps the only thing that could overshadow news out of Europe, at least for one day, is Facebook's debut as a public company on the Nasdaq Stock Market.

Facebook is expected to begin trading before noon, the day after the online social network raised $16 billion in an initial public offering. Its established market value, $104 billion, already exceeds that of Walt Disney, McDonald's and Amazon.com.

Friday's uptick for futures bucks a trend, and U.S. stocks appear to be headed for their first losing month since September, with Europe dominating headlines.

Dow Jones futures are down more than 5 percent in May and the S&P and Nasdaq are down 6 percent to 7 percent.

And as representatives of the G-8 head for Camp David this weekend, the situation in Europe may be growing more dire.

Ratings agency Moody's downgraded 16 Spanish banks late Thursday, three days after downgrading Italy's, noting they are vulnerable to huge losses on government debt.

And after an election in Greece that brought in political parties opposed to bailouts for the beleaguered country, the Fitch ratings agency dropped the nation to the lowest possible grade for a country not in default Thursday.